us.zuercher.gpx2map.image.generic
Class GenericImageFactory

java.lang.Object
  us.zuercher.gpx2map.image.generic.GenericImageFactory

All Implemented Interfaces:

ImageFactory

public class GenericImageFactory
extends Object
implements ImageFactory

GenericImageFactory is a factory for GenericImage objects. Its generic insofar as it depends entirely on Toolkit to load images and only supports the image formats that the toolkit supports (GIF, JPEG, and PNG).

Author:

Stephan Zuercher

Nested Class Summary

private static class	GenericImageFactory.DrawingObserver DrawingObserver is an ImageObserver that allows callers to wait for the drawing of an image to complete.
private static class	GenericImageFactory.Observer Observer provides a base class for size and drawing observations.
private static class	GenericImageFactory.SizeObserver SizeObserver is an ImageObserver that can be waited upon to determine when an image's size data has been loaded.

Field Summary

private static byte	_00 0x00 as a byte.
private static byte	_FF 0xFF pre-cast as a byte.
private static List<ImageFormatDescriptor>	formatDescriptors List of ImageFormatDescriptor objects for our supported formats.
private static byte[][]	gifHeaders GIF file header.
static GenericImageFactory	instance The singleton instance of this image factory.
private static byte[][]	jpegHeaders JPEG file header.
private static int	minimumFileSize Minimum number of bytes from an image file necessary to determine the file's type.
private static byte[][]	pngHeaders PNG file header.
private static byte[][][]	supportedHeaders Array of supported header data.
private static Toolkit	toolkit Graphics toolkit used for loading images.

Constructor Summary

private

GenericImageFactory() GenericImageFactory is a singleton.

Method Summary

boolean	canLoad(File imageFile) Tests whether the given file contains an image in a format supported by this factory.
private boolean	canLoad(InputStream imageStream) Test the given input stream's format and return an indication of whether the format is supported or not.
boolean	canLoad(URL imageUrl) Tests whether the given URL refers to an image in a format supported by this factory.
private static GenericImage	createImage(Image javaImage)
List<ImageFormatDescriptor>	getSupportedImageFormats() Returns the ImageFormatDescriptors for image formats supported by this factory.
GenericImage	loadImage(File imageFile) Load an image from the given file name.
GenericImage	loadImage(URL imageUrl) Load an image from the given URL.
private void	testFormat(InputStream stream) Test the given input stream's format and throw an UnknownFormatException if it's not in a supported format.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

instance

public static final GenericImageFactory instance

The singleton instance of this image factory.

toolkit

private static final Toolkit toolkit

Graphics toolkit used for loading images.

_FF

private static final byte _FF

0xFF pre-cast as a byte.

See Also:

Constant Field Values

_00

private static final byte _00

0x00 as a byte.

See Also:

Constant Field Values

pngHeaders

private static final byte[][] pngHeaders

PNG file header. First element is a set of mask bytes that should be applied the remaining elements and the file data before comparison.

gifHeaders

private static final byte[][] gifHeaders

GIF file header. First element is a set of mask bytes that should be applied the remaining elements and the file data before comparison.

jpegHeaders

private static final byte[][] jpegHeaders

JPEG file header. First element is a set of mask bytes that should be applied the remaining elements and the file data before comparison.

supportedHeaders

private static final byte[][][] supportedHeaders

Array of supported header data.

minimumFileSize

private static final int minimumFileSize

Minimum number of bytes from an image file necessary to determine the file's type.

formatDescriptors

private static final List<ImageFormatDescriptor> formatDescriptors

List of ImageFormatDescriptor objects for our supported formats.

Constructor Detail

GenericImageFactory

private GenericImageFactory()

GenericImageFactory is a singleton.

See Also:

instance

Method Detail

getSupportedImageFormats

public List<ImageFormatDescriptor> getSupportedImageFormats()

Returns the ImageFormatDescriptors for image formats supported by this factory.

Specified by:

getSupportedImageFormats in interface ImageFactory

Returns:

the ImageFormatDescriptors for image formats supported by this factory.

canLoad

public boolean canLoad(File imageFile)
                throws IOException

Tests whether the given file contains an image in a format supported by this factory.

Specified by:

canLoad in interface ImageFactory

Parameters:

imageFile - the file to test

Returns:

true if the image file is in a supported format, false otherwise

Throws:

IOException - if the file cannot be read

canLoad

public boolean canLoad(URL imageUrl)
                throws IOException

Tests whether the given URL refers to an image in a format supported by this factory.

Specified by:

canLoad in interface ImageFactory

Parameters:

imageUrl - the URL to test

Returns:

true if the image URL refers a file in a supported format, false otherwise

Throws:

IOException - if the URL cannot be read

loadImage

public GenericImage loadImage(File imageFile)
                       throws IOException,
                              UnknownFormatException

Load an image from the given file name.

Specified by:

loadImage in interface ImageFactory

Parameters:

imageFile - the image to load

Returns:

a GenericImage

Throws:

IOException - if there's an error reading the file

UnknownFormatException - if the file format is not known

loadImage

public GenericImage loadImage(URL imageUrl)
                       throws IOException

Load an image from the given URL.

Specified by:

loadImage in interface ImageFactory

Parameters:

imageUrl - the image to load

Returns:

a GenericImage

Throws:

IOException - if there's an error reading the file

UnknownFormatException - if the file format is not known

testFormat

private void testFormat(InputStream stream)
                 throws IOException,
                        UnknownFormatException

Test the given input stream's format and throw an UnknownFormatException if it's not in a supported format.

Parameters:

stream - the stream to test

Throws:

IOException - if there's an error reading the stream

UnknownFormatException - if the stream's format is not supported

canLoad

private boolean canLoad(InputStream imageStream)
                 throws IOException

Test the given input stream's format and return an indication of whether the format is supported or not.

Parameters:

imageStream - the stream to test

Returns:

true if the stream is in a supported format, false otherwise

Throws:

IOException - if there's an error reading the stream

createImage

private static GenericImage createImage(Image javaImage)
                                 throws IOException

Throws:

IOException